Leclerc pushed too hard to prevent an undercut by Verstappen, Sainz ignored the red light during his pitstop. Strategy wise Binotto's explanation makes sense: Sainz' tires probably wouldn't have lasted anyway and he would not get five seconds clear of Perez and Russell, now at least he got an extra point for fastest lap.
The engine is not the most reliable though, and there will be more penalties incoming for sure.